HN Explorer

8 comments

[ 4.8 ms ] story [ 33.9 ms ] thread
hcfman
Combine microsecond GPS clock with a sound recorder on an Pi and get a cool sound localization system.
xchip
this is pretty cool, could this be achieved using android phones? If so I would like to help.
hcfman
This uses the PPS signal on a GPS to trigger an interrupt to sync the time. Not doubt you would have that on a mobile phone.

I suspect that mobile phones use NTP which could be quite a number of milliseconds out.

However, it depends what exactly you really mean with the question? It could mean many things.

Note, for gunshot localization I think someone has already built an app that I think they are trying to sell to the authorities.

Maybe I can answer better if you clarify which part you are asking could be done on a phone ?

Certainly the localization math can be.

hcfman
The localization calculations you can do on an Android, recording audio aligned to less than a millisecond of error I’m pretty sure you cannot.
xchip
well, you can use some sort of radio signal so sync a beep and use that for syncing.
hcfman
Sounds viable. A lot of beeping.
BHSPitMonkey
Are you aware of any forums/groups where people network these sorts of setups with people in their area? I live near a tech hub and have been wondering if something like this could be possible to cover a larger area or neighborhood, but I don't know anyone personally who would probably be as interested.
hcfman
Me and a bunch of friends have systems setup kilometers apart and have fun doing forensic analysis to determine where all the explosions from illegal fireworks come from.

In the Netherlands this happens several times a week in many places so there is plenty of test data.